Cottonseed meal glues of low alkalinity



Patented July 261, 1953 .oo'r'roNsEED MEAL GLUES 0F Lo l g v' ALKALINITYI` .lett1C.'Arthur,'Jr., and Joseph T. Hogan, New

Orleans, La., assignors tothe United States of America .asvrepresented`by the Secretary of vN6v Drawing. Apblicatio May s, 1951, ..eserial No.224,439

24 Claims. (Cl. 260-6) .i (Granted under Tine, 35, U. s. Code (1952),

sec.266) f Y 'Y The invention hereinvdescribed maybe manun factured byor for the Government of the United 'States' of America for"governmental purposes throughout the world without the payment to .us'

'oiany lroyalty thereon. f;

'-This"invention'relatesv to vthe production yof rglut'e fromcottonseedv meal or cake. More vpar- "ticularly it providesglues,vwhichare so proious additives-'suchlas CS2 (usually in conjunc= tion withcarbon1 tetrachloride), lime,l silicates, vvborates, alumsandtheJikevwhich'have been l found Ato. improve. the water resistance andspreadability ofthe glue. The seedmeal is generally pulverizedtoa'lour-like consistency and .suspended ordispersedina ratiorof from`rabout L 20ste .flopartsof meal in 100' parts of Aa sodium hydroxideandlime'solution containingthe ad- ','jditives yandhaving a pI-lof atleastabout,12.`

Y A"It hasbeen found thatglues having this degree of alkalinity (apI-Iof 12 or more) will stain acid woods and light-colored veneers; andconfromcottonseed meal have a particular economic advantage sincetheycan consist principally of 'I cottonseed meal, technical grade urea,and technicalgrade formaldehyde; all of which are low vcost materialscompared to the urea-formalde-` hyde resins.l I l l Thec'ottonseed'mealglues of low alkalinity provided by the process of this invention can beproduced from cottonseed meals Yor cakes from t which the oil wasremoved by screw-pressing, hydraulic pressing, or bysolvent extractionprocf esses or by other de-oiling processes conducted in theconventional manner.

It is well known that the heating 'of the meals that is sometimes donein `conventional*pressing operations denatures the protein. YLfottonseed meal glues prepared frommeallrwhlich lh'as"`r 1ot A beensubjected to extensive heating', form glue -joints which are muchstronger than those prepared fromfan extensively heatedlmeal. I'G-l'uesprepared from solvent extracted'rneals, inaccordance with the vprocessofthe invention, constitute a preferred classof compositions provided bythe invention;V vAnother preferred class"of compositionsr provided bythe invention consists of theV glues so produced from cottonseed mealswhich] have been vde-oiled in any manner' which leaves a meal containingatleast 70%, Ysoluble nitrogen as determined by suspending 2.5 gramssequently the utilization .of cottonseed meal glues has heretoiorebeen'.limited vto vthe bonding of 1 v dark-colored woods and veneers in spiteof their advantageously strong and resistant joints and low cost.A

Various attempts to produce cottonseed meal '6 glues Vof low alkalinityvhave been described. However, such processes often involve mixingpulverized' cottonseed meal with compositions such as urea-formaldehyderesins.`

formaldehyde resins are glues in their own right. f In addition,` suchresinous glues are several times as expensive as cottonseed meal. Theuse of the cottonseed meal as an extender vfor such a resinous glue,produces a glue comparable to those .producedby extending theresinousglue with Q 'various other llers such 'as inedible wheat flourand the like, and the products are much more expensive than theconventional cottonseed meal glues. y Y v We have surprisinglyVdiscovered that by dispersing a cottonseed. meal in an aqueous solu-ltion, containing formaldehyde, in which solution the principalnbasicingredient is urea; glues the commonly vused low alkalinityurea-formaldehyde glues)` and a bond shear strengthV equal The ureaofthe meal in 100 ml. of 0.5M NaClfor 3 hours at25"C."A -Apreferredmethodof producing the glues vprovided by the invention consists of dispersing`the seed meal in an aqueous solution containing urea, allowing theprotein to react with the urea,

j and adding formaldehyde to themixture. 1 The process can be conductedat temperaturesl ranging from `0to 100 C. but itV can be emciently vandeconomically conducted at substantially room temperature (20 to 40,C.).,and the employment of such temperature is, of course, preferred.

The aqueous solution can suitably contain from,0.5 to 3 partsof urea perpart of water, but

we yhave found-that particularly eiective glues are produced bytheemployment of aqueous solutions containing about l to Zparts by weight.of urea per part of water.

The time vrequired for the protein to react with the urea of coursevaries with the particuto or greater than that of urea-formaldehydeglues, can be produced. *The glues so produced' having a pI-I of lessthan 8 (less than the pH' of E lar cottonseed'meal used, the amount ofmeal used, the extent to which it is pulverized, and the temperature oftherea-c'tion. In general, times sufficient for the pulverizedcottonseed meal to become completely wetted by the solution are,sufcient When thev nreaction isconducted at about room temperature.using about 0.5 to 1 parts of a cottonseed meal (containing at least %Vsolublenitrogen and passing through a 20D-mesh screen) per part ofwaterv containing 0.5 to l part of urea, particularly suitable glues areproduced by allowing from` about 20 to 40 minutes for the reaction withurea, adding from 0.3 to 0.5 part formaldehyde and 1 to 1.5 parts ofwater per part of the urea and meal mixture, and maintaining theresultant mixture for from 40 to 80 minutes at 20 to 40C.

The conventional additives such as carbon disulfide, carbontetrachloride, silicates, borates, alums, and the like which improvewater resistance and/or spreadability can be incorporated in thesuspension.

The formaldehyde can be added in any of its conventionally employedforms, but is preferably added in the form of an aqueous solution. Theamount of formaldehyde can be varied from 0.5 to 1 part per part ofurea. Particularly suitable glues have been produced by adding an amountof formaldehyde `about equal to the amount of urea, in the form of anaqueous solution.

The glues provided by the process of this invention can suitably beapplied and used in the conventional hot or cold pressing operations.

The viscosity of the glues prepared by the process of the invention willvary depending upon the concentration of meal, urea and formaldehyde andthe time they are allowed to stand as Well as upon the particularcottonseed meal used.

from 200 to 250 'poises,

The pH of the glues provided by the invention will vary principallydepending upon the concentration of urea and meal and acidic or basicadditives. Preferred glues provided by the process of the invention havea pH of from 7.5 to

7.8, but in general glues provided by the invention having a pI-I belowabout 8.5 can be applied to acid or light-colored woods without causingappreciable discoloration. v

The following examples are presented to illustrate in greater detailcertain modes of practicing the present invention and certain of itscharacteristics. Since numerous modifications can suitably be employed,the scope of the invention is dened by the claims and is not to be con-ParticularlyY suitable glues provided by the process of the inventionhave a viscosity of strued as being limitedv to the d the examples.

etails recited in EXAMPLE 1 One hundred parts of oil-free cottonseedmeal were mixed with 100 parts of urea and 100 parts of water at 25 C.for 1/2 hour. Then 270 parts of 37 percent formaldehyde solution wereslowly added to the urea-cottonseed meal reaction product. After onehour, 'the viscosity of the cottonseed meal glue was 202 poises, and thepH of the glue was 7.5.

The low alkaline cottonseed meal glue was used to bond Wood veneer withminimum alkali staining to yield plywood having dry and wet shearstrengths of about 282 and 153 pounds per square inch, respectively.

EXAMPLE 2 One hundred parts of oil-free cottonseed meal were mixed with200 parts of urea and 200 parts of water at 25 C. for 1k hour. Then 270parts of 37 percent formaldehyde solution were slowly added to theurea-cottonseed meal reaction product. After one hour, the viscosity ofthe cottonseed meal glue was 218 poises, and the pH of the glue was 7.8.

The low alkaline cottonseed meal glue Was used to bond wood veneer withminimum alkali staining to yield plywood having dry and wet shearstrengths of about 300 and 166 pounds per square inch, respectively.

EXAMPLE 34 One hundred parts of oil-free cottonseed meal were mixed with200 parts of urea and 133 parts of Water at 25 C.Y for 1/2 hour.v Then400 parts of 37 percent formaldehyde solution were slowly added to theurea-cottonseed meal reaction product. After one hour, the viscosity ofthe cottonseed meal glue was 225 poises, and the pH of the glue was 7.8.

The low alkaline cottonseed meal glue was used to bond wood veneer withminimum alkali staining to yield plywood having dry and Wet shearstrengths of about 266 and 140 pounds per square inch, respectively.

EXAMPLE 4 El'ect of urea-formaldehyde solvent for cottonseed meal andprocessing conditions on the shear strengths of glue iointsl PressingConvSh n ear Strength spready tions Solids Viscosity lbs/1,000 f 7 GlueComposltwn Percent (1 lsemg 5&1?" ne pH Dry, wood Wet, Wood D t Y compHet; Failure Failure p. s. i. p. s. i. (lha/sq. (lbs/sq.

in.,percent) u1.,perceiit) No. l

100 grains hexane-extracted meal 53 202 18 7. 5 150 150 282-50 153-30100 grams cream-. 53 202 18 7. 5 none 150 284-45 150-l5 100 grams Water53 202 18 7. 5 150 none 153-20 89-0 270 ml. 37% HCHO grams hexane-extraeted meal 43 218 18 7. 8 150 150 287-45 149-10 100 grams urea, 43 21818 7.8 200 200 292-45 159-35 100 grams Water, 43 218 18 7. 8 200 200300-60 166-30 270 ml. 37% ECHO v grams heXaneex tracted meaL. 150 gramsurea 44 225 14 7. 8 200 200 266-20 140-15 grams water. 400 inl. 37%HCHO.. Urea-formaldehyde 63 19 8.1 200 200 298-45 163-20 Glue. equalparts 45 19 8. l 200 200 264-20 127-0 1 Meal, urea, and Water reactedprior to addition of formaldehyde. 2 Average .of 20 values determinedfor 3 ply test pieces by tensile shear tester at dry (conditioned at 75F. and 32% relative humidity for 6 days) and Wet (immersed 'm water for48 hours at 77o F. prior to testing) conditions.

2 Cold pressed at 77cl F. for 1,440 minutes.

Having thus described our invention, we claim: 1. A process for theproduction of a cottonseed meal glue which comprises: reactingcottonseed meal with urea by suspending an oil-free cottonseed meal inan aqueous solution containing from about 1 to 2 parts urea and fromabout 1 to 2 parts Water per part of meal and maintaining Vthesuspension at from about 20 to 40 C. for from about 20 to 40 minutes;land reacting the .reaction product so produced with formaldehydel byVmixing it with formaldehyde in the form of an aqueous solutionintroducing from about 0.3 to 0.5. parts formaldehyde and from about 1to 1.5 parts water per part of said reaction product and maintaining theresultant mixture at from about 20 to 40 C. for from about 6 .40 to 80minutes until said mixture has a viscosity of from about 200 to250poises.`

2. The process of claim 1 wherein the cottonseed meal is an oil-freehexane extracted cottonseed meal.

JETT C. ARTHUR, JR. JOSEPH T. HOGAN.

References Cited in the file of this patent UNITED STATES PATENTSNumber. Name Date 1,245,975 Satow 1 Nov. 16, 1917 2,249,003 Julian et alJuly 15, 1941 2,332,801 Leonardson et al. Oct. 26, 1943

1. PROCESS FOR THE PRODUCTION OF A COTTONSEED MEAL GLUE WHICH COMPRISES:REACTING COTTONSEED MEAL WITH UREA BY SUSPENDING AN OIL-FREE COTTONSEEDMEAL IN AN AQUEOUS SOLUTION CONTAINING FROM ABOUT 1 TO 2 PARTS UREA ANDFROM ABOUT 1 TO 2 PARTS WATER PER PART OF MEAL AND MAINTAINING THESUSPENSION AT FROM ABOUT 20 TO 40* C. FOR FROM ABOUT 20 TO 40 MINUTES;AND REACTING THE REACTION PRODUCT SO PRODUCED WITH FORMALDEHYDE BYMIXING IT WITH FORMALDEHYDE IN THE FORM OF AN AQUEOUS SOLUTIONINTRODUCING FROM ABOUT 0.3 TO 0.5 PARTS FORMALDEHYDE AND FROM ABOUT 1 TO1.5 PARTS WATER PER PART OF SAID REACTION PRODUCT AND MAINTAINING THERESULTANT MIXTURE AT FROM ABOUT 20 TO 40* C. FOR FROM ABOUT 40 TO 80MINUTES UNTIL SAID MIXTURE HAS A VISCOSITY OF FROM ABOUT 200 TO 250POISES.